“Sniff” lung cancer biomarkers in breath using N-doped monolayer WS2: A theoretical feasibility

Nanosensor-based artificial olfaction is a promising non-invasive and inexpensive method for early lung cancer diagnosis. In particular, the development of breath sensors for the selective detection of biomarkers is one of the most critical challenges. In this study, the sensing performance of the Nitrogen-doped WS2 monolayer (N-WS2) to three volatile organic compound molecules, i.e., 2,3-Dimethylhexane (Dim), Styrene (Sty), and Toluene (Dol), as typical lung cancer biomarkers was evaluated with the aid of the density functional theory (DFT) calculations. The normal small gas molecules (N2,O2, CO2, and H2O) were also taken into account. Their corresponding adsorption behaviors, recovery times, and response differences were carefully discussed. The N-WS2 monolayer possesses relatively strong adsorption capacities for the biomarkers with detectable recovery times at room temperature. The variation ratio of the electrical conductivity of N-WS2 is clear enough to be used as the response signal for the determination of the biomarkers in exhaled gases. Moreover, the humidity will not affect the sensing performance of the N-WS2 monolayer. These theoretical results demonstrate that the N-WS2 monolayer is a promising gas sniffer for preliminary lung cancer diagnosis.